Air core reactors are inductive devices used in high voltage power transmission, distribution and industrial applications. Configurations and designs include devices which have a number of applications, including filtering out harmonics, shunt devices which compensate for introduction of capacitive reactive power, and devices which limit short circuit currents. Air core reactors, typically placed in outdoor environments, are formed with a series of concentrically positioned, spaced-apart winding layers, referred to as packages, each having a cylindrical configuration. These designs allow for some cooling of the winding layers by movement of air convection currents between the spaced-apart winding layers. The winding layers are positioned between upper and lower current carrying members, sometimes referred to as spider units. The spider units comprise a series of arms radiating along a plane and away from a central position in a star configuration.
Among other functions, the spider units may serve as line terminals for connecting power lines and for connecting the winding layers in an electrically parallel configuration. The reactors are normally installed with the spider units occupying a horizontal orientation with respect to an underlying horizontal ground plane so that the major axis of the cylindrical configuration extends vertically upward from the ground plane. For a single reactor, or for the lower-most reactor in a stacked configuration of two or more reactors, the winding layers are supported above the ground by the lower spider unit and a series of insulators and structural leg members which extend from the lower spider unit to the ground.
Sound radiated from air core reactors can be a serious irritant to population groups living nearby. In the past, these sound levels have been reduced with sound shields, typically in the form of self-supporting fiberglass enclosures, that completely surround one or more reactors. To effectively mitigate the sound, these shields must be substantially larger than the reactors and utilize sound absorbing material, e.g., acoustically insulating foam. Consequently, the cost of the shield could exceed the cost of the reactor it surrounds.